Wavelength converting material, and light emitting device

ABSTRACT

A wavelength converting material includes a luminous core and a first protective layer. The first protective layer covers the luminous core, in which the first protective layer includes silicon dioxide, and in silicon atoms of the silicon dioxide, the silicon atom of the zeroth configuration (Q 0 ) does not connect with any siloxy group, and the silicon atom of the first configuration (Q 1 ) connects with one siloxy group, and the silicon atom of the second configuration (Q 2 ) connects with two siloxy groups, and the silicon atom of the third configuration (Q 3 ) connects with three siloxy groups, and the silicon atom of the fourth configuration (Q 4 ) connects with four siloxy groups, in which a total amount of the silicon atoms of the third configuration and the fourth configuration is greater than a total amount of the silicon atoms of the zeroth configuration, the first configuration and the second configuration.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Taiwan Application Serial Number108117555, filed May 21, 2019, which is herein incorporated byreference.

BACKGROUND Field of Invention

The present disclosure relates to a wavelength converting material and alight emitting device.

Description of Related Art

Quantum dots and phosphor powders are common wavelength convertingmaterials, which are applied to light emitting diodes for absorbinglight from a light emitting diode chip and emitting light of anothercolor, and the lights are then mixed to form a desired light color.Further, the quantum dot or phosphor powder may be with the lightemitting diode device to serve as a backlight of a display or a pixel ofa display.

However, the quantum dot of the wavelength converting material issusceptible to destruction by oxygen and moisture, which results inreduced luminance and lifetime. Therefore, there is a need for atechnical solution to reduce damage to the wavelength convertingmaterial by oxygen and moisture, thereby improving the reliability ofthe wavelength converting material.

SUMMARY

According to one aspect of the present disclosure, a wavelengthconverting material includes a luminous core and a first protectivelayer. The first protective layer covers the luminous core, in which thefirst protective layer includes silicon dioxide, and in silicon atoms ofthe silicon dioxide, each of the silicon atoms is one of a zerothconfiguration (Q⁰), a first configuration (Q¹), a second configuration(Q²), a third configuration (Q³) and a fourth configuration (Q⁴), andthe silicon atom of the zeroth configuration (Q⁰) does not connect withany siloxy group, and the silicon atom of the first configuration (Q¹)connects with one siloxy group, and the silicon atom of the secondconfiguration (Q²) connects with two siloxy groups, and the silicon atomof the third configuration (Q³) connects with three siloxy groups, andthe silicon atom of the fourth configuration (Q⁴) connects with foursiloxy groups, in which a total amount of the silicon atoms of the thirdconfiguration (Q³) and the fourth configuration (Q⁴) is greater than atotal amount of the silicon atoms of the zeroth configuration) (Q⁰), thefirst configuration (Q¹) and the second configuration (Q²).

According to one or more embodiments of the present disclosure, thetotal amount of the silicon atoms of the third configuration (Q³) andthe fourth configuration (Q⁴) is greater than 80% based on a totalamount of the silicon atoms of the silicon dioxide of 100%.

According to one or more embodiments of the present disclosure, in a²⁹Si nuclear magnetic resonance spectrum of the wavelength convertingmaterial, there are a peak of the third configuration (Q³) in a range offrom −95 to −105 ppm and a peak of the fourth configuration (Q⁴) in arange of from −105 to −115 ppm.

According to one or more embodiments of the present disclosure, theluminous core includes a quantum dot material.

According to one or more embodiments of the present disclosure, asurface of the quantum dot material is subjected to a modificationtreatment, and the modification treatment includes a ligand exchangetreatment, a microemulsification treatment, an organic material coating,an inorganic material coating, an embedding into pores of mesoporousparticles or a combination thereof.

According to one or more embodiments of the present disclosure, theluminous core includes a phosphor powder material.

According to one or more embodiments of the present disclosure, asurface of the phosphor powder material is subjected to a modificationtreatment, and the modification treatment includes an organic materialcoating, an inorganic material coating or a combination thereof.

According to one or more embodiments of the present disclosure, theorganic material used for coating includes poly(methyl methacrylate)(PMMA), polyethylene terephthalate (PET), polyethylene naphthalate(PEN), polystyrene (PS), polyvinylidene difluoride (PVDF), polyvinylacetate (PVAC), polypropylene (PP), polyamide (PA), polycarbonate (PC),polyimide (PI), epoxy or silicone.

According to one or more embodiments of the present disclosure, theinorganic material used for coating includes nitride, metal oxide,silicon oxide or a combination thereof.

According to another aspect of the present disclosure, the lightemitting device includes a solid state semiconductor light emittingelement and an above-described wavelength converting material. The solidstate semiconductor light emitting element is configured to emit a firstlight. The wavelength converting material absorbs a portion of the firstlight and emits a second light with a wavelength different from awavelength of the first light.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will be better understood from the followingdetailed description when read in conjunction with the drawings. Itshould be emphasized that, depending on the standard practice in theindustry, the features are not drawn to scale and are for illustrativepurposes only. In fact, the size of the feature can be arbitrarilyincreased or decreased for the purpose of clarity.

FIG. 1 is a cross-sectional view of a wavelength converting material 100according to some embodiments of the present disclosure.

FIG. 2 is a cross-sectional view of a wavelength converting material 200according to some embodiments of the present disclosure.

FIG. 3 illustrates a light emitting device 300 according to someembodiments of the present disclosure.

FIG. 4 is a ²⁹Si nuclear magnetic resonance spectrum of a firstprotective layer 120 of Embodiment 1 of the present disclosure.

FIG. 5 is a ²⁹Si nuclear magnetic resonance spectrum of a firstprotective layer 120 of Embodiment 2 of the present disclosure.

FIG. 6 is a ²⁹Si nuclear magnetic resonance spectrum of a firstprotective layer of Comparative Embodiment 1.

FIG. 7 is a graph showing brightness versus time of Embodiment 1 of thepresent disclosure.

FIG. 8 is a graph showing brightness versus time of ComparativeEmbodiment 2.

FIG. 9 is a graph showing brightness versus time of ComparativeEmbodiment 1.

FIG. 10 is a graph showing brightness intensity versus wavelength of awavelength converting material of Embodiment 1 of the presentdisclosure.

FIG. 11 is a graph showing brightness intensity versus wavelength of awavelength converting material of Comparative Embodiment 1.

DETAILED DESCRIPTION

The following disclosure provides various different embodiments orexamples for implementing different features of the present disclosure.Specific embodiments of components and arrangements are described belowto simplify the content of the present disclosure. The embodiments aremerely examples and are not intended to be limiting. For example, in thefollowing description, a first feature formed over or above a secondfeature includes an embodiment in which the first feature is in directcontact with the second feature, and may also include an embodiment inwhich the first feature is not in direct contact with the secondfeature.

Further, the component symbols and/or letters in the various embodimentsof the present disclosure may be repeated. This repetition is for thesake of simplicity and does not indicate a relationship between thevarious embodiments and/or configurations. Furthermore, in the presentdisclosure, a following feature formed, connected to, and/or coupled toanother feature, may include an embodiment in which the features are indirect contact, and may also include an embodiment in which anadditional feature is inserted to the formed features such that thefeatures are not in direct contact. Further, for ease of description,spatially relative terms (e.g., “beneath”, “below”, “lower”, “over”,“upper”, and the like) may be used herein to describe a relationshipbetween one component or feature and another component (or components)or feature (or features). The spatially relative terms are intended toencompass different orientations of the components in use or operation.

The present disclosure provides a wavelength converting material, whichhas excellent luminescence lifetime and maintains good brightness duringlong-time luminescence.

Please refer to FIG. 1, which illustrates a cross-sectional view of awavelength converting material 100 according to some embodiments of thepresent disclosure. The wavelength converting material 100 includes aluminous core 110 and a first protective layer 120. The luminous core110 includes a quantum dot material or a phosphor powder material.

The first protective layer 120 covers the luminous core 110, in whichthe first protective layer 120 includes silicon dioxide. It is worthnoting that the silicon dioxide of the first protective layer 120includes a plurality of silicon atoms, and each of the silicon atoms isone of a zeroth configuration (Q⁰), a first configuration (Q¹), a secondconfiguration (Q²), a third configuration (Q³) and a fourthconfiguration (Q⁴). Specifically, the silicon atom of the zerothconfiguration (Q⁰) does not connect with any siloxy group, and thesilicon atom of the first configuration (Q¹) connects with one siloxygroup, and the silicon atom of the second configuration (Q²) connectswith two siloxy groups, and the silicon atom of the third configuration(Q³) connects with three siloxy groups, and the silicon atom of thefourth configuration (Q⁴) connects with four siloxy groups. That is, inQ^(n), n is the number of other silicon atom(s) where the silicon atomconnected to through the oxygen atom, and n may be 0, 1, 2, 3 or 4.

In some embodiments, the silicon dioxide of the present disclosure maybe made using a silicon precursor, such as a siloxy precursor ortetraethoxysilane.

The structure of the siloxy precursor is as shown in the followingstructural formula (1):

in which R is a linear or branched alkyl group, but is not limitedthereto.

The structure of tetraethoxydecane is as shown in the followingstructural formula (2):

For example, the silicon atom of the zeroth configuration (Q⁰) may be asilicon precursor (e.g., above-mentioned tetraethoxysilane), which hasthe structure as shown in the above structural formula (2). In thestructural formula (1) and the structural formula (2), the silicon atomis not connected to another silicon atom through the oxygen atom, sothat the silicon atom in the structural formula (1) and the structuralformula (2) is the zeroth configuration (Q⁰).

Further, in some embodiments, the zeroth configuration (Q⁰) may bepresent in an intermediate compound after hydrolysis, which includes thefollowing structural formula (3):

In some embodiments, the silicon atom of the first configuration (Q¹)may include the following structural formula (4):

in the structural formula (4), the silicon atom denoted by Q¹ is thefirst configuration (Q¹), which is connected to one siloxy group. Inother words, the silicon atom of the first configuration (Q¹) isconnected to another silicon atom through one oxygen atom. The firstconfiguration (Q¹) is a chain structure.

In some embodiments, the second configuration (Q²), the thirdconfiguration (Q³), and the fourth configuration (Q⁴) may be as shown instructural formula (5):

in the structural formula (5), the silicon atom denoted by Q² is thesecond configuration (Q²), and the silicon atom denoted by Q³ is thethird configuration (Q³), and the silicon atom denoted by Q⁴ is thefourth configuration (Q⁴). It is worth noting that the secondconfiguration (Q²) is a long chain structure, and the thirdconfiguration (Q³) and the fourth configuration (Q⁴) are networkstructures. In addition to the silicon atoms and oxygen atoms describedabove, other functional groups in the structure may vary depending onthe precursor from which the silicon dioxide is made.

In the silicon dioxide of the first protective layer 120 of the presentdisclosure, a total amount of the silicon atoms of the thirdconfiguration (Q³) and the fourth configuration (Q⁴) is greater than atotal amount of the silicon atoms of the zeroth configuration (Q⁰), thefirst configuration (Q¹) and the second configuration (Q²). Since thesilicon dioxide of the first protective layer 120 is mainly composed ofthe third configuration (Q³) and the fourth configuration (Q⁴) of thenetwork structure, the coated quantum dot material may greatly improvethe tolerance.

In some embodiments, the total amount of the silicon atoms of the thirdconfiguration (Q³) and the fourth configuration (Q⁴) is greater than80%, such as 85%, 90%, 95% or 99%, based on a total amount of thesilicon atoms of the silicon dioxide of 100%. In other embodiments, anamount of the silicon atoms of the fourth configuration (Q⁴) is greaterthan an amount of the silicon atoms of the third configuration (Q³). Insome embodiments, in the silicon dioxide, the amount of the siliconatoms of the fourth configuration (Q⁴) is greater than a total amount ofthe silicon atoms of the zeroth configuration (Q⁰), the firstconfiguration (Q¹), the second configuration (Q²) and the thirdconfiguration (Q³).

The first protective layer of the present disclosure can protect theluminous core from damage by external factors (e.g., oxygen and moisturedamage), and thus the wavelength converting material has excellentluminescence lifetime. In particular, the silicon dioxide of the firstprotective layer of the present disclosure has a composition of thesilicon atoms of specific configurations, which can achieve a protectiveeffect superior to a general protective layer.

In some embodiments, the luminous core 110 includes a quantum dotmaterial. For example, the quantum dot material includes CdSe, CdTe,ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS,ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS,CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe,CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, GaN, GaP, GaAs,GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb,GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb,InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP,GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs,InAlPSb, SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS,PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, SnPbSTe, CsPbX₃or Cs₄PbX₆, in which X is chlorine, bromine, iodine or a combinationthereof.

In addition, in some embodiments, in addition to being coated by thefirst protective layer, a surface of the quantum dot material may befurther treated with other kinds of modification treatments, such as aligand exchange treatment, microemulsification treatment, an organicmaterial coating, an inorganic material coating, an embedding into poresof mesoporous particles or a combination thereof. The modified quantumdot material has a better luminescence lifetime.

Further, the organic material used for coating described above includespoly(methyl methacrylate) (PMMA), polyethylene terephthalate (PET),polyethylene naphthalate (PEN), polystyrene (PS), polyvinylidenedifluoride (PVDF), polyvinyl acetate (PVAC), polypropylene (PP),polyamide (PA), polycarbonate (PC), polyimide (PI), epoxy or silicone.

The inorganic material used for coating described above includesnitride, metal oxide, silicon oxide or a combination thereof.

In other embodiments, the luminous core 110 includes a phosphor powdermaterial. For example, the phosphor powder material includes Y₃Al₅O₁₂(YAG), LuYAG, GaYAG, Ba₂SiO₄:Eu²⁺, Sr₂SiO₄:Eu²⁺,(Mg,Ca,Sr,Ba)₃Si₂O₇:Eu²⁺, Ca₈Mg(SiO₄)₄Cl₂:Eu²⁺, (Mg, Ca, Sr, Ba)₂SiO₄:Eu²⁺, Sr(LiAl₃N₄): Eu²⁺, Si_(6-n)Al_(n)O_(n)N_(8-n)(n=0-4.2):Eu²,SrS:Eu²⁺, SrGa₂S₄:Eu²⁺, ZnS:Cu⁺, ZnS:Ag⁺, Y₂O₂S:Eu²⁺, La₂O₂S:Eu²⁺,Gd₂O₂S:Eu²⁺, SrGa₂S₄:Ce³⁺, ZnS:Mn²⁺, SrS:Eu²⁺, CaS: Eu²⁺,(Sr_(1-x)Ca_(x))S: Eu²⁺, (Ca, Mg,Y)Si_(w)Al_(x)O_(y)N_(z):Ce²⁺,Ca₂Si₅N₈: Eu²⁺, (Ca, Mg,Y)Si_(w)Al_(x)O_(y)N_(z):Eu²⁺, (Sr, Ca,Ba)Si_(x)O_(y)N_(z):Eu²⁺), K₂SiF₆:Mn⁴⁺, K₂TiF₆:Mn⁴⁺ or K₂GeF₆:Mn⁴⁺.

In some embodiments, in addition to being coated by the first protectivelayer, a surface of the phosphor powder material may be further treatedwith other kinds of modification treatments, for example, the surface ofthe phosphor powder is coated with an organic material, an inorganicmaterial, or the organic material and the inorganic material. Asdescribed above, the organic material used for coating includespoly(methyl methacrylate), polyethylene terephthalate, polyethylenenaphthalate, polystyrene, polyvinylidene difluoride, polyvinyl acetate,polypropylene, polyamide, polycarbonate, polyimide, epoxy or silicone.The inorganic material used for coating includes nitride, metal oxide,silicon oxide or a combination thereof.

Please refer to FIG. 2, which is a cross-sectional view of a wavelengthconverting material 200 according to some embodiments of the presentdisclosure. In some embodiments, different from the wavelengthconverting material 100, the wavelength converting material 200 furtherincludes a second protective layer 130, and the second protective layer130 covers the first protective layer 120. The second protective layer130 may include an organic material or an inorganic material, such aspoly(methyl methacrylate), polyethylene terephthalate, polyethylenenaphthalate, polystyrene, polypropylene, polyamide, polycarbonate,polyimide, epoxy, siloxy resin, TiO₂, SiO₂, BN or ZnO.

Since the second protective layer 130 may also protect the luminous core110 and prevent the luminous core 110 from being damaged by externalfactors (e.g., oxygen or moisture), the wavelength converting material200 has more excellent luminescence lifetime. As described above, theluminous core 110 may be coated with an organic material or an inorganicmaterial. Therefore, in other embodiments, the configurations of thefirst protective layer 120 and the second protective layer 130 may beinterchanged. That is, the second protective layer 130 covers theluminous core 110, and the first protective layer 120 covers the secondprotective layer 130.

In addition, please refer to FIG. 3, which illustrates a light emittingdevice 300 according to some embodiments of the present disclosure. Thelight emitting device 300 includes a solid state semiconductor lightemitting element 310 and a wavelength converting material 320. Thewavelength converting material 320 may be the above-described wavelengthconverting material 100 or wavelength converting material 200. The solidstate semiconductor light emitting element 310 is configured to emit afirst light 330, and the wavelength converting material 320 absorbs aportion of the first light 330 and emits a second light 340 with awavelength different from a wavelength of the first light 330. In someembodiments, the light emitting device 300 may be a white light devicethat is applied to illumination or a backlight of the display. In someembodiments, the light emitting device 300 may emit red, blue or greenlight for use in a variety of fields.

In some embodiments, the solid state semiconductor light emittingelement 310 may be an organic light emitting diode, an inorganic lightemitting diode, or an organic-inorganic light emitting diode.

The present disclosure also provides some embodiments and comparativeembodiments according to the present disclosure. In Embodiment 1, afirst protective layer of the present disclosure was used to cover aquantum dot material. In Embodiment 2, a first protective layer of thepresent disclosure was used to cover a phosphor powder material. InComparative Embodiment 1, a conventional protective layer was used tocover a quantum dot material. In Comparative Embodiment 2, a quantum dotmaterial did not include a protective layer.

Please refer to FIG. 4, which is a ²⁹Si nuclear magnetic resonancespectrum of the first protective layer 120 of Embodiment 1 of thepresent disclosure. The structure of Embodiment 1 is as shown in FIG. 1,and the first protective layer of the present disclosure was used tocover the quantum dot material.

In the ²⁹Si nuclear magnetic resonance spectrum, the chemical shift ofthe zeroth configuration (Q⁰) was in a range of from about −73 ppm toabout −85 ppm, and the chemical shift of the first configuration (Q¹)was in a range of from about −81 ppm to about −90 ppm, and the chemicalshift of the second configuration (Q²) was in a range of from about −90ppm to about −95 ppm, and the chemical shift of the third configuration(Q³) was in a range of from about −98 ppm to about −104 ppm, and thechemical shift of the fourth configuration (Q⁴) was in a range of fromabout −108 ppm to about −111 ppm. The above ranges of chemical shiftsmight include an error of ±3.0 ppm. For example, the chemical shift ofthe zeroth configuration (Q⁰) might be in a range of from about −70 ppmto about −88 ppm.

Therefore, as can be seen from FIG. 4, the first protective layer 120 ofEmbodiment 1 of the present disclosure was mainly composed of thesilicon atoms of the third configuration (Q³) and the fourthconfiguration (Q⁴). After integrating areas of the ranges correspondingto the configurations respectively, it could be known that a totalamount of the silicon atoms of the third configuration (Q³) and thefourth configuration (Q⁴) of the present disclosure was greater thanthat of the zeroth configuration (Q⁰), the first configuration (Q¹) andthe second configuration (Q²). Moreover, in the ²⁹Si nuclear magneticresonance spectrum, the wavelength converting material of the presentdisclosure had a peak of the silicon atoms of the third configuration(Q³) in a range of from −95 to −105 ppm and a peak of the silicon atomsof the fourth configuration (Q⁴) in a range of from −105 to −115 ppm.

Please refer to FIG. 5, which is a ²⁹Si nuclear magnetic resonancespectrum of the first protective layer of Embodiment 2. The structure ofEmbodiment 2 is as shown in FIG. 1, and the first protective layer ofthe present disclosure was used to cover the phosphor powder material.It can be seen from FIG. 5 that the first protective layer of Embodiment2 was also mainly composed of the silicon atoms of the thirdconfiguration (Q³) and the fourth configuration (Q⁴). Therefore,regardless of whether the first protective layer covers the quantum dotmaterial or the phosphor powder material, the total amount of thesilicon atoms of the third configuration (Q³) and the fourthconfiguration (Q⁴) can be greater than that of the zeroth configuration(Q⁰), the first configuration (Q¹) and the second configuration (Q²). Inother words, the first protective layer of the present disclosure can beapplied to the quantum dot materials, and can also be applied to thephosphor powder materials.

Please refer to FIG. 6 which is a ²⁹Si nuclear magnetic resonancespectrum of the first protective layer of Comparative Embodiment 1.Amounts of the silicon atoms of the third configuration (Q³) and thefourth configuration (Q⁴) of the first protective layer of ComparativeEmbodiment 1 were significantly less. After integrating areas of theranges corresponding to the configurations respectively, it could befound that a total amount of the silicon atoms of the zerothconfiguration (Q⁰), the first configuration (Q¹), and the secondconfiguration (Q²) of Comparative Embodiment 1 was greater than that ofthe third configuration (Q³) and the fourth configuration (Q⁴).

Next, please refer to FIG. 7, which is a graph showing brightness versustime of Embodiment 1 of the present disclosure. In general, a lifetimeof a light emitting element is evaluated by L₅₀, which is the time whenthe brightness of the light emitting element is attenuated to 50% of theoriginal. The degrees of decay of Embodiment 1 at different currentswere small, in which when a current was 5 mA, the brightness wasmaintained at more than about 80% after 3,000 hours. The curve L1 was atrend line of data at the current of 5 mA according to Embodiment 1, andit could be found that L50 of the curve L1 exceeded 8,000 hours.

The quantum dot material of Comparative Embodiment 2 did not include aprotective layer. Please refer to FIG. 8, which is a graph showingbrightness versus time of Comparative Embodiment 2. As can be seen fromFIG. 8, although the brightness decayed in the first 50 hours is small,the brightness decayed extremely fast after more than 50 hours. At acurrent of 5 mA, the brightness after 500 hours was only about 70%. Thecurve L2 was a trend line of data at the current of 5 mA according toComparative Embodiment 2, and L50 of the curve L2 was only about 1,000hours.

In Comparative Embodiment 1, a conventional protective layer was used tocover a quantum dot material. Please refer to FIG. 9, which is a graphshowing brightness versus time of Comparative Embodiment 1. Comparedwith Embodiment 1, it can be found that Comparative Embodiment 1 hadlarge degrees of decay at different currents. In the case of a currentof 5 mA, the brightness remained only about 75% after 500 hours. Thecurve L3 was a trend line of data at the current of 5 mA according toComparative Embodiment 1, and L50 of the curve L3 was also only about1,500 hours.

It can be seen from FIGS. 7 and 9 that the use of the first protectivelayer of the present disclosure can significantly increase theluminescence lifetime of the wavelength converting material. Since thetotal amount of the silicon atoms of the third configuration (Q³) andthe fourth configuration (Q⁴) of the first protective layer is greaterthan that of the zeroth configuration (Q⁰), the first configuration (Q¹)and the second configuration (Q²), it can protect the luminous core moreeffectively and avoid damage from external factors.

FIG. 10 is a graph showing brightness intensity versus wavelength of thewavelength converting material of Embodiment 1 of the presentdisclosure. FIG. 11 is a graph showing brightness intensity versuswavelength of the wavelength converting material of ComparativeEmbodiment 1. Referring to FIG. 10 and FIG. 11 at the same time, itcould be found that degree of decay of the brightness intensity of eachwavelength range of Embodiment 1 after illuminating for more than 1,300hours was extremely small, but in Comparative Embodiment 1, afterilluminating for 500 hours, degree of decay of the brightness intensityof each wavelength range were large. Specifically, between 500 nm and550 nm, the degree of decay of the brightness intensity of ComparativeEmbodiment 1 was large, and the degree of decay of the brightnessintensity of Embodiment 1 was relatively small. This result showed thatin addition to the increase in the luminescence lifetime of thewavelength converting material, the present disclosure could maintainthe color emitted by the wavelength converting material under a longperiod of operation.

The present disclosure provides the wavelength converting material whichcan greatly increase the luminescent lifetime of the wavelengthconverting material. Specifically, the wavelength converting material ofthe present disclosure has the first protective layer, and the firstprotective layer has specific configurations of the silicon atoms, sothat the protective effect of the first protective layer is moreexcellent. It is worth noting that the first protective layer of thepresent disclosure is applicable not only to the quantum dot materialsbut also to the phosphor powder materials. Further, the presentdisclosure also provides the light emitting device including theabove-described wavelength converting material.

The features of various embodiments or examples are summarized above sothat those skilled in the art can better understand the aspects of thepresent disclosure. Those skilled in the art should appreciate that thepresent disclosure may be readily utilized as a basis for designing ormodifying other processes and structures to achieve the same objectivesand/or achieve the same advantages of the embodiments described herein.Those skilled in the art should also appreciate that such equivalentstructures do not depart from the spirit and scope of the presentdisclosure, and various changes, substitutions and alterations hereinmay be made without departing from the spirit and scope of the presentdisclosure.

What is claimed is:
 1. A wavelength converting material, comprising: aluminous core; and a first protective layer covering the luminous core,wherein the first protective layer comprises silicon dioxide, and in aplurality of silicon atoms of the silicon dioxide, each of the siliconatoms is one of a zeroth configuration) (Q⁰), a first configuration(Q¹), a second configuration (Q²), a third configuration (Q³) and afourth configuration (Q⁴), and the silicon atom of the zerothconfiguration (Q⁰) does not connect with any siloxy group, and thesilicon atom of the first configuration (Q¹) connects with one siloxygroup, and the silicon atom of the second configuration (Q²) connectswith two siloxy groups, and the silicon atom of the third configuration(Q³) connects with three siloxy groups, and the silicon atom of thefourth configuration (Q⁴) connects with four siloxy groups, wherein atotal amount of the silicon atoms of the third configuration (Q³) andthe fourth configuration (Q⁴) is greater than a total amount of thesilicon atoms of the zeroth configuration (Q⁰), the first configuration(Q¹) and the second configuration (Q²).
 2. The wavelength convertingmaterial of claim 1, wherein the total amount of the silicon atoms ofthe third configuration (Q³) and the fourth configuration (Q⁴) isgreater than 80% based on a total amount of the silicon atoms of thesilicon dioxide of 100%.
 3. The wavelength converting material of claim1, wherein in a ²⁹Si nuclear magnetic resonance spectrum of thewavelength converting material, there are a peak of the thirdconfiguration (Q³) in a range of from −95 to −105 ppm and a peak of thefourth configuration (Q⁴) in a range of from −105 to −115 ppm.
 4. Thewavelength converting material of claim 1, wherein the luminous corecomprises a quantum dot material.
 5. The wavelength converting materialof claim 4, wherein a surface of the quantum dot material is subjectedto a modification treatment, and the modification treatment comprises aligand exchange treatment, a microemulsification treatment, an organicmaterial coating, an inorganic material coating, an embedding into poresof mesoporous particles or a combination thereof.
 6. The wavelengthconverting material of claim 5, wherein the organic material used forcoating comprises poly(methyl methacrylate) (PMMA), polyethyleneterephthalate (PET), polyethylene naphthalate (PEN), polystyrene (PS),polyvinylidene difluoride (PVDF), polyvinyl acetate (PVAC),polypropylene (PP), polyamide (PA), polycarbonate (PC), polyimide (PI),epoxy or silicone.
 7. The wavelength converting material of claim 5,wherein the inorganic material used for coating comprises nitride, metaloxide, silicon oxide or a combination thereof.
 8. The wavelengthconverting material of claim 1, wherein the luminous core comprises aphosphor powder material.
 9. The wavelength converting material of claim8, wherein a surface of the phosphor powder material is subjected to amodification treatment, and the modification treatment comprises anorganic material coating, an inorganic material coating or a combinationthereof.
 10. The wavelength converting material of claim 9, wherein theorganic material used for coating comprises poly(methyl methacrylate)(PMMA), polyethylene terephthalate (PET), polyethylene naphthalate(PEN), polystyrene (PS), polyvinylidene difluoride (PVDF), polyvinylacetate (PVAC), polypropylene (PP), polyamide (PA), polycarbonate (PC),polyimide (PI), epoxy or silicone.
 11. The wavelength convertingmaterial of claim 9, wherein the inorganic material used for coatingcomprises nitride, metal oxide, silicon oxide or a combination thereof.12. A light emitting device comprising: a solid state semiconductorlight emitting element configured to emit a first light; and awavelength converting material, comprising: a luminous core; and a firstprotective layer covering the luminous core, wherein the firstprotective layer comprises silicon dioxide, and in a plurality ofsilicon atoms of the silicon dioxide, each of the silicon atoms is oneof a zeroth configuration (Q⁰), a first configuration (Q¹), a secondconfiguration (Q²), a third configuration (Q³) and a fourthconfiguration (Q⁴), and the silicon atom of the zeroth configuration(Q⁰) does not connect with any siloxy group, and the silicon atom of thefirst configuration (Q¹) connects with one siloxy group, and the siliconatom of the second configuration (Q²) connects with two siloxy groups,and the silicon atom of the third configuration (Q³) connects with threesiloxy groups, and the silicon atom of the fourth configuration (Q⁴)connects with four siloxy groups, wherein a total amount of the siliconatoms of the third configuration (Q³) and the fourth configuration (Q⁴)is greater than a total amount of the silicon atoms of the zerothconfiguration (Q⁰), the first configuration (Q¹) and the secondconfiguration (Q²), wherein the wavelength converting material absorbs aportion of the first light and emits a second light with a wavelengthdifferent from a wavelength of the first light.
 13. The light emittingdevice of claim 12, wherein the total amount of the silicon atoms of thethird configuration (Q³) and the fourth configuration (Q⁴) is greaterthan 80% based on a total amount of the silicon atoms of the silicondioxide of 100%.
 14. The light emitting device of claim 12, wherein in a²⁹Si nuclear magnetic resonance spectrum of the wavelength convertingmaterial, there are a peak of the third configuration (Q³) in a range offrom −95 to −105 ppm and a peak of the fourth configuration (Q⁴) in arange of from −105 to −115 ppm.
 15. The light emitting device of claim12, wherein the luminous core comprises a quantum dot material.
 16. Thelight emitting device of claim 15, wherein a surface of the quantum dotmaterial is subjected to a modification treatment, and the modificationtreatment comprises a ligand exchange treatment, a microemulsificationtreatment, an organic material coating, an inorganic material coating,an embedding into pores of mesoporous particles or a combinationthereof.
 17. The light emitting device of claim 12, wherein the luminouscore comprises a phosphor powder material.
 18. The light emitting deviceof claim 17, wherein a surface of the phosphor powder material issubjected to a modification treatment, and the modification treatmentcomprises an organic material coating, an inorganic material coating ora combination thereof.
 19. The light emitting device of claim 18,wherein the organic material used for coating comprises poly(methylmethacrylate) (PMMA), polyethylene terephthalate (PET), polyethylenenaphthalate (PEN), polystyrene (PS), polyvinylidene difluoride (PVDF),polyvinyl acetate (PVAC), polypropylene (PP), polyamide (PA),polycarbonate (PC), polyimide (PI), epoxy or silicone.
 20. The lightemitting device of claim 18, wherein the inorganic material used forcoating comprises nitride, metal oxide, silicon oxide or a combinationthereof.